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Corporation of ^unocc (Ekctrititg <§>upplu department 



DESCRIPTION OF THE GENERATING STATION 



SOUVEWR 



OF THE VISIT BY 



THE BRITISH ASSOCIATION 

TO DUNDEE 



SEPTEMBER 1912 



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of D. 
8 1919 



ttnrp0rati0it of Bmttor. 



Members of Electricity Committee, 1911-12. 



Lord Provost JAMES URQUHART. 



COUNCILLOR JOHN M. NAIRN, Convener. 



Bailie W. DON. 
Bailie ALEX. SPENCE. 
Bailie W. S. MELVILLE. 
Bailie W. FORWELL. 



Bailie J. K. FOGGIE. 
Councillor A. R. MEGHAN. 
Councillor w. H. BUIST. 
Councillor G. A. JOHNSTON. 



W. H. BLYTH MARTIN, Town Clerk. 



H. RICHARDSON, Chief Electrical Engineer and Manager. 



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^$1^ | Brief History and Description 
mSm ? of the Undertaking 














HE CITY OF DUNDEE, with a population of 170,000 inhabitants, is the third city in 
Scotland, and covers an area of 4,881 acres. The city is the centre of the jute industry of 
Great Britain, importing about 220,000 tons annually. There are about 100 mills and factories 
with approximately 60,000 horse power. Shipbuilding and iron foundries provide employment 

for a large portion of the inhabitants. The Admiralty within the last three years have leased a portion 

of the Harbour and Docks, and have formed there a Submarine Base. 

Dundee was one of the first cities to recognise the advantages of a general supply of Electricity, but it 
is only within the last six or seven years that its use has been extended to the larger consumer. 

In 1890 Dr John Hopkinson and Professor J. A Ewing were consulted, and a provisional order was 
obtained by the Dundee Gas Commissioners. The area of supply contemplated in this order was restricted 
to the centre of the city and covered an area of 320 acres only. In 1893 the supply was commenced for 
lighting and power purposes, and from then up to 1900 slow but steady progress was made. The 
generating station was built in Dudhope Crescent Road, and it was decided to supply direct current at 200 
volts on the three wire system. Bare copper strip resting on insulators in concrete culverts was laid 



throughout the area of supply. The first plant consisted of three Lancashire boilers 24 feet long by 7 feet 
in diameter, and six Willans-Siemens direct coupled generating sets, two of 43 k.w. and four of 87 k.w. 





Ex-Provost Brownlee, 
Convener from 1893 to 1906. 



Bailie W. Don, 
Convener from 1906 to 1910. 



Additional generating sets were added in 1895 an d 1897, when all the floor space shown in the original 
plan was occupied. In 1897 an Act was passed making the area of supply co-terminus with the Burgh. 



Progress was rather slow but steady up to 1900. In the latter year the Corporation took over the horse 
and steam tramways of the city from the local operating company, and after some hesitation decided to 
electrify the whole system. Extensions have since been made to the tramways, and at present the length 
of the route opened for traffic is 14-J miles. The price for current charged to the tramway department had 
been steadily reduced from i^d. to i^d. per unit, this year further reduction has been made to id. per unit, 
which charge is inclusive of the cost of upkeep of the overhead equipment and cables, also charges on 
special plant and cables. 

To meet the increasing demand from private consumers, as well as the extra load caused by the 
conversion of the tramway system, large extensions were made. Three generating sets, totalling 1,150 
k.w., were installed, and the original engine-room lengthened, as well as a second engine-room being 
erected alongside of it. Also, a further boiler-house and new chimney were built. The new generating 
sets were started running in 1900. Additional generators were put in during 1901 and 1903. The present 
Chief Engineer and Manager upon taking up his duties in 1903 practically remodelled the works. 
Extensive alterations were made in the arrangements of the plant, steam piping, switchboards, &c, and the 
effect was a considerable reduction in costs. Also, the supply pressure was changed from the 200 to 400 
volts three wire system ; this, of course, greatly increased the capacity of the feeders. 

Notwithstanding all the improvements which had been made, however, the business increased within 
recent years to such an extent, and the inherent disadvantages of the site, far removed from rail and water, 
and the want of elasticity in the system of generation and distribution, became more and more evident, 
when greater amounts of current had to be transmitted over the larger area. 

After careful consideration of reports, designs, and estimates from Mr H. Richardson, it was decided 
that an up-to-date station should be erected at the Stannergate, supplying extra high tension, three phase 
alternating current at 6,600 volts, 50 cycles per second, to various sub-stations. In 1907 the building of 
the Carolina Port Main Generating Station was started, and the new system was finished in 1909 at 



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Scale of Feet 
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Plan of Main Generating Station. 



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a cost of over £100,000. The supply was started in July of the same year and has been eminently 
satisfactory in every way. The official inauguration of the new system took place on the 23rd of February 
1910, when it was opened by Professor J. A. Ewing, C.B., F.R.S., Director of Naval Education. 

Ex-Provost W. Brownlee, who has taken a deep interest in electrical matters from the beginning, was 
the first Convener of the Department. He was succeeded in 1906 by Bailie W. Don, whose enthusiasm 
made itself manifest. The present Convener, Councillor J. M. Nairn, was elected in 1910, and, like his 
predecessors, has shown deep interest in the work of the Department. 

MAIN GENERATING STATION. 

The main generating station is situated at Carolina Port, about ih miles from the centre of the city 
and 560 feet from the River Tay. The site occupies an area of roughly one acre, but there is ample ground 
in the vicinity for extensions. The present main buildings average 120 feet long by 132 feet wide, and 
consist of a steel framework filled in with brick on three elevations and corrugated iron on the fourth to 
allow for easy extension. The roof is of wood and slates, supported on steel principals 15 feet apart, and 
has large roof lights running the whole length of the building. The arrangement is shewn in plan and 
sectional elevation respectively. A distinctive feature of the buildings is the large windows in the north 
and east elevations. In the boiler-house especially the great amount of light and the white-glazed bricks 
of the boiler and economiser settings give a pleasing effect, and is conducive to good work on the part of 
the boiler-house staff. 

Foundations. — The ground upon which the station is built was reclaimed from the river some 
twenty-two years ago. A large percentage of the subsoil is the refuse of the local gasworks., and of 
no use whatever for bearing permanent loads. Numerous borings were made and good rock was found 
30 to 33 feet below the surface. It was ultimately decided to build the whole foundation on reinforced 



10 




PLAN ON A.A. 




PLAN ON B.B. 



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ELEVATION 

Scale of Feet 

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STRAINERS AT 
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Plan and elevation of Pump House. 



11 



concrete piles, grouping them where the heavier weights had to be carried, and then to form a reinforced 
concrete raft over the whole, constructed to the various levels required. More than 300 piles, 14 inch 
diameter, were driven down to the rock. The raft varies in thickness from 4 feet to \\ inches. 




Main Generating Station. 

Buildings. — The whole of the structural steel work of the main buildings was supplied and erected 
by the Clyde Structural Iron Company, who started erecting in the middle of 1908, and the brickwork 
was carried out by Messrs A. & T. Craig, who began early in October. Immediately it was possible, 



12 



although the building was barely started, the work of getting in the plant was arranged for. The roofs 
are of blue slate, nailed to wood boarding, and have roof lights running the whole length of the building. 
The amount of light arranged for throughout the works is quite a distinctive feature of the design, and, 



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Upper Part of Pump Room : Main Station in distance. 

together with the first-class dressing-rooms and lavatories, conduces to the most healthy working con- 
ditions. With the exception of the roof, no wood is used in the construction, the whole of the window 
frames, and practically all the doors and stairs, being of iron or steel. 



13 



Engine Room. — The engine room is 120 feet long by 50 feet wide, and 49 feet 9 inches high from 
the floor level to the eaves. The upper floor is 14 feet 9 inches above the lower level, and is constructed 
of reinforced concrete on the Columbian system, and finished with red Terrano. Large open wells are 
left in the upper floor, as well as chequer-plates, to allow of the overhead crane being used when over- 
hauling the auxiliary plant below. As will be seen in the plan, the upper floor is cut short at the east end 
and the part of the lower floor at that end is reserved for sub-station machinery. 

The Switch House. — The switch house is 120 feet long 15 feet 3 inches wide, and has three 
floors for extra high-tension switchgear. 

Battery Room. — The battery room is situated directly above the switch house, and is of the same 
dimensions. The room is lighted by two rows of roof lights extending the whole length, and large venti- 
lators carry away the fumes. As the extra high-tension switchgear is immediately below, special attention 
had to be given to the construction of the floor to make it acid proof. Reinforced concrete on the 
Columbian system was used, covered with blue adamantine clinkers, laid on a bed of cement and grouted 
with bitumen. The floor is laid to fall towards the drain which is also acid proof. 

Staff Accommodation. — In the continuation of the switch house and battery room towards the 
east, rooms are reserved for the station superintendent and staff. 

Boiler House. — The boiler house is 105 feet long by 40 feet wide and 53 feet 9 inches from the 
basement to the eaves. Provision in height has been left for thermal storage should conditions warrant the 
addition of this in future. 

Bunker House. — The bunker house is 105 feet long, 20 feet wide, and 65 feet from the ash base- 
ment to the eaves. It may be seen in section on the right-hand side of the boilers. The firing floor is 4 
feet above ground level ; this was arranged to allow for the ash basement to be lit and ventilated by 
windows. An inclined roadway at the north door of the boiler house provides easy access to the firing 
floor for carting coal in case of emergency as well as for handling plant. 



14 




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A small workshop, store, and lodge are situated at the north-east corner of the site, while a weigh 
house and locomotive shed are also provided. 

As far as practicable, the unit system has been carried out in the design of the work. The station as 
at present put down is complete and symmetrical on each side of its north and south centre line. In the 
arrangement of the buildings the possibility of the use of internal combustion prime movers and generators 
has been kept constantly in view. 

Chimney. — Near the centre of the building is situated the chimney, which is 9 feet internal diameter 
and 200 feet high. It rests on a reinforced concrete foundation 4 feet in thickness, and is supported on 
twenty-five reinforced concrete piles. The chimney is built of red brick and has a fire-brick lining. A 
central division is erected inside to a height of 26 feet above the firing level. 

MACHINERY AND PLANT. 

Electric Locomotive. — A small electric locomotive, supplied by the British Thomson-Houston Co., 
is employed for shunting the coal wagons, and takes its current from overhead wires by two trolley arms. 
It has two motors, and is capable of pulling a load of 20 tons up an incline of 1 in 60 at a speed of 
6\ miles per hour. 

Coal-handling Plant. — Coal is brought to the site in railway wagons at the average level of the 
ground. This line passes over a 20-ton weighing machine, then leads through a large ring tippler situated 
over a receiving hopper. After a wagon is clamped in the tippler, the whole gradually makes a complete 
revolution, thus emptying the coal into the hopper and returning the wagon to its original position. The 
tippler is driven by an electric motor of four-brake horse power, through worm gearing, and takes two 
minutes to make a complete revolution. The rings are weighted at the top to give a central centre of 
gravity when turning with a load, an ingenious lock prevents the tippler being turned without a wagon in 
position. 



16 




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The hopper underneath the tippler is built of steel plates f inch thick, stiffened by tees and angles. It 
has a capacity of 18 tons, and is provided with a sliding- valve which regulates the flow of coal to the tray 
conveyor. The tray conveyor carries the coal from the hopper to the main conveyor, a distance of about 
45 feet. It is driven by a 2-brake horse power electric motor, and is controlled either from the tippler or 
ash basement. It discharges the coal into a rotary filler, which fills the buckets of the main conveyor 
while they are in motion. The main conveyor, which is of the gravity bucket type, was supplied by Messrs 
Babcock & Wilcox, Limited. It is about 326 feet long and has a vertical lift of 62 feet, and travels at the 
rate of 50 feet per minute. The buckets are each stamped out of a single piece of steel; they have only 
the side brackets and tipping lugs riveted. The coal is deposited in the bunkers by means of tippers, of 
which there are two to each bunker. The conveyor can only be started from the bunker floor, but can be 
stopped from either the bunker or firing floor, or from the basement. 

Bunker House. — Above the firing floor are the coal bunkers, with a capacity of about 700 
tons. They are entirely built of steel plates stiffened with tees, angles, and joists ; about 67 tons of steel 
and 8,300 rivets were used in their construction. The bottom plates are § inch, while the sides and bulk- 
heads are 5-16 inch in thickness. Special attention was given to the riveting, and the joints were caulked to 
render them as far as possible watertight. As the east bunker has been reserved for ashes, it is coated with 
a special paint to preserve the steel plates. The coal passes through a valve at the bottom of the bunker 
into measuring machines, where the amount is registered, and these run on rails, and thus the coal is 
conveyed to any of the boilers and discharged through chutes into the stocker-hoppers. 

Boilers. — There are at present four Babcock & Wilcox water-tube boilers, each having a heating 
surface of 6,182 square feet, and rated to evaporate 20,000 lbs. of water per hour, with a working pressure 
of 180 lbs. per square inch. The boilers are each fitted with the makers' improved superheater of 1,389 
square feet heating surface, which gives a superheat of about 150 degrees Fahr. ; they are supplied with 
the usual flooding and draining arrangements. There are two chain grate stokers fitted to each boiler, 



18 



with a grate area of 120 square feet, and are driven by means of an 8-brake horse power motor, erected 
immediately below the boilers in the ash basement. The motors are controlled from the firing floor. 

The brickwork settings of the boilers are faced with white enamelled bricks. The chain grates were 
designed to burn the cheapest coal. The walls of the boilers are built on the hollow principle, the spaces 
between them are filled with slag wool. The ashes descend through dumping doors at the back of the 
chain grates to the ash pits, and from there to the basement, where, after being cooled, they are elevated 
by the main conveyor to the ash bunker, from which they are discharged by chutes into railway waggons 
or carts, as desired. In the boiler house there is a Simmance & Abady combined CO. 2 and draught 
recorder, a large illuminated steam pressure gauge, showing the pressure in the main steam pipe, and also 
a recording pressure guage. 

Economisers and Flues. — Special attention was given when designing the flues to make them as 
short as practicable and to avoid sharp curves. To facilitate cleaning, sliding doors have been provided in 
the bottom of the main flues, so that tne soot may be dropped into barrows at the ash basement level, and 
transferred to the main conveyor. 

Behind each battery of boilers is situated a Green's Economiser of 360 tubes. They are erected 
immediately above the main flues on either side of the chimney, and so arranged that the hot gases pass 
through them in an upward direction before entering the chimney. The economisers raise the feed water 
to a temperature of about 190 Fah. Owing to the intention of burning the cheapest fuel, special arrange- 
ments had to be made for cleaning both the economisers and flues. Under each section of tubes a soot pit 
is formed with a double slope leading to a trough, where there is a screw conveyor to discharge the soot 
into trucks, from whence it is taken to the ash bunker by the main conveyor. The screw conveyors are 
worked through worm gearing from the scraper mechanism, which is driven by a 4-brake horse power 
electric motor. All the dampers are of the horizontal butterfly type. 

Feed Pumps. — Contrary to the usual power station practice, the feed pumps are placed in the 
engine room on the lower floor. There are two steam-driven Weir feed pumps, each capable of delivering 



20 



8,ooo gallons of water per hour against the boiler pressure of 180 lbs. per square inch. Besides the ordinary 
stop valve on the pump, there is a regulating valve with a long spindle extending through the brickwork 
of the chimney into the boiler-house, by means of which the firemen can regulate the speed of the pump. 
This regulating valve is designed so that it does not cut off the steam altogether, and thus allows the pump 
to be always in working condition. Above the wheel on the long spindle is a gauge giving the pressure of 
the feed water in the feed pumps, and on this gauge the strokes of the pump can be plainly observed. 

The exhaust steam from the cylinders of the feed pump, owing to the presence of oil, is not allowed to 
mix with the turbine exhaust, but is passed through a coil in the hot well, where it is used to heat the feed 
water. The whole of the feed water piping is of mild steel, with flanges screwed on. 

Steam Piping. — The steam piping was designed to be as simple and short as possible. An 8-inch 
main header runs the length of the boiler-house, to which each boiler is connected by a 6-inch branch pipe. 
From the header two 8-inch pipes lead to the turbines, after passing through separators, attached to which 
are Poole steam traps, discharging the condensed steam into the hot wells. The main steam pipes are of 
mild steel with flanges and branches rivetted on. An expansion bend is fitted horizontally in the main 
header between the two sets of boilers, care being taken when fixing to spring the bend into position, so 
that the amount of extension was equal to half the total expansion of the pipes under working conditions. 
To allow of free expansion in the pipe line, the supports are of the roller type, and only two points of 
anchorage were arranged, viz., at the middle of each set of boilers. The flanges on all pipes are to the 
British engineering standards. 

Steam Turbines. — There are two steam turbines coupled direct to generators, each set having a 
capacity of 2,000 kilowatts, but capable of dealing with an overload of 25% for two hours, and 50% for one 
hour. The turbines are of the Willans-Parsons type. The sections of blading are made up in half rings, 
both for the casing and rotor, and these rings are held in position in dovetailed grooves by means of 



21 



caulking strips. On each turbine there is a hand-operated overload valve, which admits high-pressure 
steam to the second expansion rings. The governor is of the centrifugal type, and acts directly on the 
throttle valve. It is also fitted with electrical control gear, which is operated from the switchboard. 
Forced lubrication is used. There is also a small hand oil pump provided to flush the bearings before 
starting. The turbines are fitted with pressure and vacuum gauges, also a tachometer. 




Vertical Spindle Motors in Pump Room. 

Condensing Plant. — Immediately below each turbine is a Contraflo Surface Condenser of 3,400 
square feet cooling surface. To allow for expansion and prevent distortion of the turbine casing, the 
condenser is mounted on springs. Each condenser has about 2,000 tubes, § inch diameter by 8 feet in 
length. These and the casing are prevented from pitting by a patent arrangement, in which blocks of 



22 



metal, electro-positive to the brass and iron, are fixed to the tube plates. There is an automatic 
atmospheric valve above each condenser, with an 1 8-inch exhaust pipe opening to the atmosphere. A 
three-throw Edwards' air pump is connected to each set, driven by means of gearing from an electric 
motor. A force pump, at the extremity of the air pump crank shaft, lifts the discharge to a Lea Recording 




Main Oil Switch Galley. 

water meter on the upper floor, where after being measured it gravitates to the hot wells. In this type of 
meter the water is made to flow through a V-notch, its depth being recorded by a plunger and float. Thus 
a constant record of the steam taken by the turbine is obtained. The hot wells are situated on the lower 



23 



engine room floor, having a capacity of 8,500 gallons each. The tanks are made of \ inch steel plates, 
stiffened by stays and angles. In a conspicuous place easily seen from the upper floor, floats and 
weight indicators give the levels of the water in the hot wells. 

Circulating Water. — The circulating water for the condensers is obtained from the River Tay. 
The maximum rise and fall of the tide is 18 feet, and the tops of the condensers are 28*5 feet above the 
lowest water level. In order to reduce the power required to circulate the large amount of water over this 
height, and also to avoid the necessity for constant regulation due to the varying head on the pumps, it 
was decided to lay the system of piping in the form of a large syphon. A reinforced concrete pump room, 
14 feet internal diameter and 27 feet deep from the ground level to the bottom floor, was sunk at the water- 
side. This pump room was built in sections, the lowest one having a steel cutting edge. The ground in 
the inside was excavated, and the section sunk by means of heavy weights. After one section was sunk, 
another was built on the top of it, and the process repeated. At the side of the pump room, next to the 
river, are two settling tanks, constructed with reinforced concrete sheet piles. Removable covers are pro- 
vided for cleansing purposes. 

On the pump room floor are fixed two 16-inch diameter vertical spindle centrifugal pumps, driven 
direct by vertical electric motors of 63-brake horse power each, fixed at ground level. The pumps are put 
below the lowest water level, so that water could always be obtained. The motors are started and 
controlled from the engine room in the station, and to allow of this, automatic reflux valves are fitted at 
the pumps. These valves gave a little anxiety at first, owing to the shock with which they closed. This, 
however, was considerably lessened by fitting a small reverse valve on the main one. 

The motors are powerful enough to deliver the full quantity of water required should the syphonic 
action on the system fail altogether. The pump room has a glass roof, and a number of iron platforms 
are at various levels, to allow of access to the several shaft bearings, &c. A small centrifugal pump driven 
by an electric motor is used for drainage when required. Had it been practicable, the pipes would have 
been laid below the lowest water level, in order to reduce the chances of air leakage should the syphon 



24 



break, but the expense cf this was too great, so the pipes were laid at a depth only partly below water 
level at highest tides. 

The main pipe lines consist of 30-inch diameter cast-iron pipes, supported on a reinforced concrete 
raft of T section, carried on reinforced concrete piles 26 feet apart. The distance between the pump- 
room and generating station is about 785 feet, and between the station and discharge end about 736 
feet. The pipes are ^5-inch thick, with spigot and faucet joints (lead was used for joints in the ground, 
flanges in the engine-room). Owing to the nature of the ground, the greatest precautions were taken 
to protect the pipes. They were coated internally and externally with Dr Angus Smith's solution, 
then asphalted yi of an inch thick on the outside, and covered with puddled clay to a thickness of 
6 inches after they were laid. 

The outlet pipe passes through the concrete wall of the Eastern Wharf, and then turns downward, 
ending in a bell-mouth bend, which is 2 feet below the lowest water level. 

The level of the water in the condensers is 19/9 feet above Ordnance datum, and on test a mercury 
gauge showed a vacuum of 22 - 8 feet of water, while the tide was 227 feet below this level. The 
measurements were only approximate owing to fluctuations, but they show that the water was running 
full bore. At another time the mercury gauge indicated 200 feet, while the tide was actually 20T feet 
below this point. 

Main Generators. — The two main Dick Kerr generators are capable of giving 2,000 kilowatts each, 
generating three-phase current, 50 cycles per second at 6,600 volts when running at a speed of r,500 
revolutions per minute. The stator body is a single casting, and is arranged to slide lengthwise to give 
access to the rotor. 

The rotor has four pole pieces, and is of very strong construction. Natural ventilation is used, cold air 
being drawn through specially constructed passages below the bed plates. Direct coupled to each 
generator is an exciter of i8'5 kilowatts at 125 volts. 



25 



Auxiliary Plant.— As a stand-by for exciting the main generators and for other auxiliary purposes, 
there are two direct current sets, with Willan's central valve II type engines, direct coupled to Siemen's 
bi-polar generators, giving 6co amperes at 200 volts. 




Foundation of Chimney before Concreting, 
showing Steel Reinforcements. 

A small booster on the upper engine-room floor, consisting of a 23-brake horse power motor and a 
15 kilowatt generator, is used for charging the battery. 

Near the main entrance, and on the lower engine-room floor, is situated the converting machinery, 
one set consisting of a three-phase 6,600 volt motor, coupled direct to a 300 kilowatt direct-current dynamo, 



26 



generating at 400 to 460 volts, and another set with a three- phase motor as described, coupled direct 
between two direct current generators of 150 kilowatts each, generating at 200 to 230 volts. 

A 25-ton electric travelling crane runs the whole length of the engine room, and provides for the 




Generating Plant at Dudhope Crescent Road. 

efficient and quick handling of the engine-room plant for repairing, &c. Separate motors are provided for 
handling, lifting, &c. The crane was supplied by Messrs Alexander Jack & Coy., Motherwell. 

Battery. — The battery is situated on the fourth floor of the switch-house, and consists of 102 Tudor 
cells in lead-lined wood boxes, supported on glass oil-insulators. 



Switch-Gear. — The extra high tension switch-gear occupies three floors, and is contained in moulded 
concrete cells, no brickwork being used. The ground floor is occupied by the cable dividing boxes, static- 
dischargers, and isolating switches. The bus-bars, which are on the first floor, are in duplicate, and the two 
sets can be put in parallel through an oil switch. The oil switches are placed on the second floor, which is 
easy of access from the switch gallery. All oil switches are of the electrically operated remote control 
type, and have two breaks per pole. Each phase is contained in a separate cell. The opening and closing 
of the switches is effected by powerful springs. The mechanism is so arranged that after the switch is 
either opened or closed the motor prepares the spring for the next operation. The whole of the switch- 
gear was supplied by the British Thomson Houston Company. The control board for the extra high 
tension switch-gear is situated on a gallery in the engine room, eleven feet above the upper floor 
level. Coloured lamps on the control board indicate the opening or closing of the oil switches. 
Synchroscopes with indicating lamps are mounted on swing panels at either end of switchboard ; also 
frequency indicators are mounted on the same panel. 

On the feeder and motor generator panels are triple pole time-limit overload relays, and on the 
generator panels are Andrews reverse power relays ; also a Tirrell regulator is used to keep the voltage 
constant notwithstanding the varying load. 

The direct current switchboard is also situated on the gallery. 

On the engine-room floor, underneath the control board gallery, are two auxiliary power switchboards, 
one controlling the battery supply. The other is connected to the direct current bus-bars. Both boards 
are of white marble, with one and four panels respectively. 

TRANSMISSION CABLES. 

The extra high tension mains consist of three core, paper insulated, lead covered cables armoured with 
two layers of steel tape, and a layer of jute impregnated with preservative to protect the armour. A coating 
of compound was poured on after cables were laid. Immediately below the lead, though insulated from it, 



L= 



28 



is the Board of Trade copper earth shield. The cables are laid direct in the ground at a depth of 3 feet 6 
inches to 4 feet, and covered with specially shaped hard burnt tiles to give warning of their presence, and 
protect them from damage. At present two cables of "i square inch section run direct to Dudhope and 
Ciepington Sub-stations, and two of '05 square inch from the former to Lochee Sub-station, making a total 
length of about 12 miles. The above were manufactured and laid by the British Insulated and Helsby 
Cables, Limited. The cables used for extensions are by the Union Cable Company. 

SUB-STATIONS. 

There are at present sub-stations in the following districts : — Dudhope in the Central, Downfield 
the Northern, Ciepington the North-Eastern, Lochee the North-Western, and the main generating 
sub-station in the South-Eastern. 

All sub-stations are supplied from Carolina Port with three-phase alternating current at a pressure 
of 6,300 volts, which is transformed to 400 volts direct current for general supply, and 500 to 550 volts 
for traction by means of rotary converters. 

Each rotary converter is provided with a 610 Kilovolt-Ampere static transformer of the oil-cooled 
type. The 6,300 volt three-phase current is transformed down to six-phase at about 190 volts, at which 
pressure it is fed into the rotary converters. Mounted on the same shafts are alternating boosters, which 
give the wide range of voltage regulation, and induction motors, to run the converters up to speed before 
synchronising. 

In the Lochee and Ciepington sub-stations the transformers and rotaries, which were made by the 
British Westinghouse Company, are placed on the ground floor, while the low and extra high tension 
switchboards are situated on galleries about 8 feet above the floor level. 

The extra high-tension switchgear is mounted in concrete cells similar to those in the main station. 
The mechanism of the switches is controlled by long rods attached to handles on the switchboard panels. 
In addition to the oil break switches, isolating links are provided on each bus-bar for use whilst the high- 



29 




Clepington Sub-Station, showing Rotary Converters and High-Tension Switch Gear, 

with their Transformers. 



30 



tension apparatus is under repair. On both incoming and outgoing extra high tension feeders are static 
dischargers, the incoming feeders have also reverse current relays. 




Engine Room at Dudhope Crescent Road, with Sub-Station Machinery and 
High-Tension Switch Gear in foreground. 



The high-tension instruments are mounted on isolated white marble panels, and include the following :— 
Volt-meters, ammeters, syiicroscopes. frequency and power factor indicator 



)rs. 



31 



The direct current switchboards are of white marble, and are arranged for the 400 volt supply to be 
separate from 500 volt for traction. 

At Dudhope there are three sets of 550 kilowatt installed in part of the engine-room of the original 
generating station, and are arranged to run in parallel on the direct current side with the existing steam- 
driven generators. 

Clepington has two sets of 550 kilowatt each, while at Lochee two 250 kilowatt sets are quite large 
enough to supply the district. Downfield has recently been erected, and the arrangements are different to 
the other Sub-stations, as both machinery and switchboards are on the ground floor level. The rotary 
converter is only 100 kilowatt capacity, and is self syncronising but in other respects it is similar to those 
above-mentioned. 

Owing to the ever increasing demands for large power installations near the Docks, and the present 
heavy loads that are on the mains in that area, it has been found necessary to build a Sub-station in the 
district. The site chosen is immediately behind the Customs House. The work of building is at present 
being carried out by the contractors. The foundations are built on concrete piles by the Hennebique 
Company of Yorkshire. 

OLD WORKS AT DUDHOPE CRESCENT ROAD. 

A brief description follows of the plant of the old generating station in its present state. 

The boiler-house is j6 feet long by 62 feet wide. There is a raised cartway from which coal is 
tipped in front of the boilers. The coal bunkers are below the roadway, and can store about 100 tons. 

There are four Lancashire boilers, 30 feet long and 8 feet in diameter, and two Babcock and Wilcox 
water-tube boilers of 3,500 square feet of heating surface, fitted with superheaters. The last two boilers are 
fitted with chain-grate stokers, but all the coal has to be dealt with by hand shovelling. 

Flue-gases pass through a Green's economiser of 960 tubes on their way to the chimney, which is 10 
feet in diameter and 210 feet high. 



32 



There are two steam-driven feed pumps, one of the duplex type by Messrs Tangye, and one by Messrs 
G. & J. Weir, Limited, of 2,000 gallons per hour capacity. The bulk of the work is, however, done by two 
Royce electrically-driven pumps of 1,200 and 3,000 gallons per hour respectively. These pumps are 
installed in two rooms, which contain the condensing plant also, and draw the water from tanks below the 
floors. 

There are five main generating sets of 825, 495, 445, and two of 330 kilowatt capacity. The engines 
are all of Willans type, but the generators were made by Messrs Parker, Limited, the International Electric 
Company, and Messrs Dick, Kerr, & Co. They are all adapted for giving direct current at 400 to 460 
volts as shunt machines, and 500 to 550 when compound. Two steam-driven balancing sets (formerly main 
generators), and also a Crompton motor balancer, are also installed. 

The steam pressure is 160 lbs. per square inch, and all the engines exhaust into a common pipe. 

There are two surface condensers with 2,000 square feet of cooling surface, with Edwards air and 
centrifugal circulating pumps. All the auxiliary machinery is electrically driven. The water is pumped to 
the top of two cooling towers situated on the boiler-house roof. 

The condensed water is freed from oil by a Harris- Anderson purifier, and is used for boiler feed. 

The main Siemens switchboard is of marble. The generator panels are arranged for changing over 
from lighting to traction. The lighting feeders are at one end of the board, and the traction feeders are on 
a separate black slate board at right angles to the main switchboard. 

THE TRACKLESS TROLLEY ROUTE. 

Dundee was one of the first cities to investigate the possibilities of Trackless Trolley Traction. Two 
or three years ago the question was gone into, but it is only recently that it took definite form. 

The route chosen was Clepington Road, which connects two very busy tramway sections, viz., Man-field 
and Downfield routes, at Forfar Road and Strathmartine Road respectively. 



33 



The length of track is 2,110 yards. Two sets of overhead wires have been run the whole length, with 
loops at each end, thus enabling the cars to return without having to shift the trolley arms, and the wires 





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Electric Locomotive with Wagon entering Tippler. 

are spaced to allow two cars at the same time to pass a vehicle in the middle of the road. The overhead 
work adopted is the span wire system. The poles, of which there are about 115, are erected at each side 
of the roadway to give greater flexibility to the cars for passing traffic. Brooklyn strain insulators are used 



34 



to carry the span wires, which are held in position on the poles by straps. The distance between poles 
is 38 feet, and the average width of roadway is 27 feet 




Tippler with Coal Wagon inverted. 



The trolley wires are No. 00 hard drawn copper of double groove type, carried by mechanical ears iS 
inches long, and supported by twin hangers of 12 inch centres. 



Three section boxes are placed at equal distances along the route, and at these points air gap section 
insulators are inserted. 

Guard wires are erected where telephone lines cross the track. Special insulated crossings are arranged 




Engine Room at Dudhope Crescent Road in 1901, 
showing first Generating Sets installed. 

at the Forfar Road end to enable the trackless cars to use the ordinary system when going to the sheds 
Bases and collars have been omitted from the poles to reduce the cost of erection. 



36 



STATISTICS, 

The progress of the undertaking since its inception in 1893 has been somewhat varied. During the 
earlier period, progress was comparatively slow, then came a very successful time, followed by a slackening 
off, while during the last few years the increase of business has been remarkable. 

In 1901, eight years after the supply was started, the units sold for all purposes amounted to 1,041,800, 
with a revenue of £12,661. In 1907 this had been increased to 4,008,413, with a revenue of £31,809, and 
at the end of the last financial year totalled 8,354,466 with a revenue of £49,366. The average selling price 
to consumers showed a large decrease — in 1901 the price was 2'g pence ; in 1907, rgi pence ; and last 
year had dropped to 142 pence. 

The net profit which the department has been able to show has during the last few years been 
considerable. As evidence of this it is necessary to mention that large alterations and extensions to the 
buildings, plant, and mains which have been carried out during the last seven years at a cost of £16,000 
has been paid entirely out of revenue, also the sum of £30,000 has been paid out of revenue (exclusive of 
Sinking Fund) towards the reduction of Capital. In addition to this the department has been able to 
steadily build up a Reserve Fund, which presently stands at £14,356. 

For year ending 30th April 1912 the net profit, after payment of Interest and Sinking Fund, amounted 
to £10,338. The progress which has been made during the last seven or eight years has made it possible 
to steadily reduce the price of current to consumers. For lighting which in 1904 was charged at a flat rate 
of 4d. per unit is now charged on the sliding scale, the maximum price being 3^d. and the minimum 2d. 
The price for power, which used to be a flat rate of 2d. to all consumers, has also been put on a more 
satisfactory basis and the sliding scale introduced, the maximum in this case being lid. and a 
minimum fd. To those who can guarantee a minimum use, a maximum price of fd. is quoted as an 
alternative. Specially low rates are also quoted for heating and cooking purposes, viz., i^-d. to §d. 



37 





The Capital Account of the undertaking at present stands at £298,86 1, while the sum redeemed by 
Sinking Fund amounts to £59,694. The balance of debt at 30th April 191 2 was £234.885. 

It is quite evident that the public are realising the immense advantages of Electricity, and the very 
cheap prices at which it is supplied in Dundee. Since the opening of the new generating station and sub- 
stations the sale of current has gone up by leaps and bounds, and in order to deal with the increasing 
demand extensions to the plant are to be carried out immediately at Carolina Port. 




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One of the earliest Generating Sets. 





38 



^able showing the 'Progress of the Electricity Department since its beginning 

in 1893. 



Year. 


Units Sold. 


Revenue. 


Average 

Selling Price 

to Consumers. 


Year. 


Units Sold. 


Revenue. 


Average 

Selling Price 

to Consumers. 


1^93 


66,228 


^i,379 


5d. 


1903 


2,609,718 


£24,042 


2*2 id. 


1894 


156,843 


3,267 


5d. 


I9O4 


2,868,566 


27.2"7 


2-28d. 


1895 


202,437 


4,217 


4-98d. 


1905 


3,067,624 


28,154 


2"20d. 


1896 


254,27s 


5,221 


4'92d. 


1906 


3,439,231 


30,923 


2"I 5cl. 


1897 


333,187 


6,015 


4'47d. 


1907 


4,008,413 


31,809 


1 -9 id. 


1898 


451,942 


7,267 


3 -86d. 


1908 


4,719,085 


35,901 


vgd. 


1899 








I909 


5,173,036 


37,610 


I75d. 


I9OO 


618.352 


9,031 


3"Sd. 


I9IO 


6,144,927 


39,908 


i'55d- 


I9OI 


1,041,800 


12,661 


2 - 9d. 


191 I 


7720,018 


46,047 


'•43d. 


I902 


1,859,943 


18,529 


2'39d. 


1912 


8,354,466 


49,366 


14. id. 



NOTE.— Owing to a change in the date of ending the financial year, the results of 1 899 are not comparable, 

and have been omitted 



39 



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